Racket

ABSTRACT

A tennis racket includes throats. Each throat includes a fiber reinforced layer and a vibration damper. The vibration damper is surrounded by the fiber reinforced layer. The fiber reinforced layer includes a plurality of reinforcement fibers and a matrix. The reinforcement fibers are typically carbon fibers. The material of the matrix is a resin composition whose base material is an epoxy resin. The vibration damper is formed of a polymer composition. The polymer composition contains a base polymer. The base polymer is preferably a styrene-isoprene-styrene block copolymer or an acrylic elastomer.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Japanese PatentApplication No. 2020-101333, filed on Jun. 11, 2020, the entiredisclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to rackets for use in, for example,tennis.

Description of the Related Art

When a player hits a ball with a tennis racket, the racket vibrates. Thevibration propagates to the player, thereby causing discomfort to theplayer.

Japanese Laid-Open Patent Application Publication No. 2002-045444discloses a racket frame including a fiber reinforced layer and avibration absorber. The vibration absorber is inserted in the fiberreinforced layer. The vibration absorber can suppress the vibration thatpropagates to the player.

The vibration absorber disclosed in Japanese Laid-Open PatentApplication Publication No. 2002-045444 has insufficient adhesion to thefiber reinforced layer. Such a vibration absorber impairs the stiffnessof the frame. A racket that is inferior in stiffness is also inferior inrebound performance.

An object of the present invention is to provide a racket that is notonly capable of suppressing the vibration that propagates to the player,but also has excellent stiffness.

SUMMARY OF THE INVENTION

A racket according to the present invention includes a frame. The frameincludes a fiber reinforced layer and a vibration damper joined to thefiber reinforced layer. The fiber reinforced layer includes areinforcement fiber and a matrix whose base material is an epoxy resin.A material of the vibration damper is a polymer composition whose basematerial is a styrene-isoprene-styrene block copolymer or an acrylicelastomer.

In the racket according to the present invention, the vibration damperdamps vibration that occurs at the frame. Therefore, vibration thatpropagates to a player using the racket can be suppressed. This allowsthe player to have an excellent feel at impact. The vibration damper isexcellent in adhesion to the epoxy resin of the fiber reinforced layer.Therefore, the vibration damper does not significantly impair thestiffness of the racket. The racket not only provides an excellent feelat impact, but also has excellent stiffness.

The frame may include a head, two throats, and a shaft. Preferably, eachthroat includes the vibration damper.

Preferably, a thickness of the vibration damper is greater than or equalto 0.10 mm but less than or equal to 1.00 mm.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a racket according to one embodiment of thepresent invention.

FIG. 2 is an enlarged exploded view of a part of the racket of FIG. 1.

FIG. 3 is an enlarged front view of a part of the racket of FIG. 1.

FIG. 4 is an enlarged sectional view taken along line IV-IV in FIG. 3.

FIG. 5 is a sectional view taken along line V-V in FIG. 4.

FIG. 6 is an enlarged sectional view of a part of the racket of FIG. 5.

FIG. 7 is a perspective view showing a part of a manufacturing processof the racket of FIG. 1.

FIG. 8 is a sectional view of a part of a racket according to anotherembodiment of the present invention.

FIG. 9 is a sectional view of a part of a racket according to yetanother embodiment of the present invention.

FIG. 10 is a sectional view of a part of a racket according to yetanother embodiment of the present invention.

FIG. 11 is a sectional view of a part of a racket according to yetanother embodiment of the present invention.

FIG. 12 is a front view of a racket according to yet another embodimentof the present invention.

FIG. 13 is an enlarged sectional view taken along line XIII-XIII in FIG.12.

FIG. 14 is a front view of a racket according to yet another embodimentof the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the present invention is described in detail based onpreferred embodiments with appropriate reference to the accompanyingdrawings.

FIGS. 1 and 2 show a tennis racket 2. The tennis racket 2 includes aframe 4, a grip 6, an end cap 8, a grommet 10, and a string 12. Thetennis racket 2 can be used in regulation-ball tennis. In FIG. 1, anarrow X represents the width direction of the tennis racket 2, and anarrow Y represents the axial direction of the tennis racket 2.

The frame 4 includes a head 14, two throats 16, and a shaft 18. The head14 forms the contour of a face 20 (the face 20 will be described belowin detail). The front shape of the head 14 is substantially an ellipse.The major axis direction of the ellipse coincides with the axialdirection Y of the tennis racket 2. The minor axis direction of theellipse coincides with the width direction X of the tennis racket 2. Oneend of each throat 16 is continuous with the head 14. Each throat 16, atthe vicinity of the other end thereof, merges with the other throat 16.The throats 16 extend from the head 14 to the shaft 18. The shaft 18extends from the location where the two throats 16 merge together. Theshaft 18 is formed so as to be continuous with, and integrated with, thethroats 16. A portion of the head 14, the portion being positionedbetween the two throats 16, is a yoke 22. The frame 4 is hollow.

The main material of the frame 4 is a fiber reinforced resin. In thepresent embodiment, the matrix resin of the fiber reinforced resin is athermosetting resin. The thermosetting resin is typically an epoxyresin. The fibers of the fiber reinforced resin are typically carbonfibers. The fibers are long filament fibers.

As shown in FIG. 2, the head 14 includes a grommet groove 24. Thegrommet groove 24 is recessed from the outer peripheral surface of thehead 14. The grommet groove 24 is formed over substantially the entireperiphery of the head 14, except the yoke 22.

The head 14 further includes a plurality of holes 26. Each hole 26extends through the head 14. The plurality of holes 26 are arranged oversubstantially the entire periphery of the head 14.

The grip 6 is formed by a tape wound around the shaft 18. The grip 6suppresses a slip between a hand of a player and the tennis racket 2when the tennis racket 2 is swung. The end cap 8 is attached to the endof the grip 6.

As shown in FIG. 2, the grommet 10 includes a base 28 and a plurality ofpipes 30. The base 28 is belt-shaped. Each pipe 30 is formed so as to beintegrated with the base 28. The pipe 30 rises from the base 28. Atypical material of the grommet 10 is a synthetic resin that is softerthan the frame 4. The tennis racket 2 may include a plurality ofgrommets 10. Each grommet 10 may be spaced apart from its adjacentgrommet(s) 10. The number of pipes 30 of each grommet 10 may be one.

The grommet 10 is attached to the head 14. In a state where the grommet10 is attached to the head 14, the base 28 is accommodated in thegrommet groove 24. The base 28 may partly protrude from the grommetgroove 24. Further, in the state where the grommet 10 is attached to thehead 14, the pipes 30 extend through the respective holes 26.

As shown in FIG. 1, the string 12 is stretched on the head 14. Thestring 12 is stretched along the width direction X and the axialdirection Y. The string 12 forms a large number of threads. Of thestring 12, portions extending along the width direction X are referredto as transverse threads 32 a. Of the string 12, portions extendingalong the axial direction Y are referred to as longitudinal threads 32b. The face 20 is formed by a plurality of transverse threads 32 a and aplurality of longitudinal threads 32 b. The face 20 generally extendsalong an X-Y plane. The face 20 may be formed by two or more strings 12.

FIG. 3 is an enlarged front view of a part of the tennis racket 2 ofFIG. 1. FIG. 3 shows the frame 4 in the vicinity of the throats 16. FIG.3 shows a pair of left and right throats 16. FIG. 4 is an enlargedsectional view taken along line IV-IV in FIG. 3. FIG. 5 is a sectionalview taken along line V-V in FIG. 4. FIG. 4 shows the right-side throat16. The left-side throat 16 has a shape that is left-right reversed fromthe shape shown in FIG. 4. FIG. 5 shows the right-side throat 16. Theleft-side throat 16 has a shape that is left-right reversed from theshape shown in FIG. 5.

FIGS. 4 and 5 show a fiber reinforced layer 34 and a vibration damper36. The fiber reinforced layer 34 includes a plurality of reinforcementfibers and a matrix. The reinforcement fibers are typically carbonfibers. The material of the matrix is a resin composition whose basematerial is an epoxy resin.

In the present embodiment, the vibration damper 36 is laminar. Thevibration damper 36 is surrounded by the fiber reinforced layer 34. Thevibration damper 36 is disposed in the outer side of the throat 16 inthe width direction (the right side in FIG. 4), i.e., disposed unevenlyin the throat 16. Alternatively, the vibration damper 36 may be unevenlydisposed in the inner side of the throat 16 in the width direction (theleft side in FIG. 4).

The vibration damper 36 is formed of a polymer composition. The polymercomposition contains a base polymer. The polymer composition may containadditive agents as necessary.

The base polymer of the vibration damper 36 is typically astyrene-isoprene-styrene block copolymer. The styrene-isoprene-styreneblock copolymer contains a polystyrene block as a hard segment and apolyisoprene block as a soft segment. One example of a sheet molded fromthe styrene-isoprene-styrene block copolymer is “KRAIBON” (trade name)available from Gummiwerk KRAIBURG GmbH & Co. KG.

The vibration damper 36 whose base material is thestyrene-isoprene-styrene block copolymer has excellent dampingperformance. When a player hits a ball with the tennis racket 2, theframe 4 vibrates. The vibration damper 36 gradually decreases theamplitude of the vibration. In the case of the tennis racket 2, theamplitude of the vibration that propagates to the player is small.Therefore, the player feels less discomfort when hitting the ball withthe tennis racket 2. The tennis racket 2 provides an excellent feel atimpact.

As previously described, in the present embodiment, the vibration damper36 is present in each throat 16. When the player hits a ball with theface 20, vibration is generated at the head 14, and the vibration isdamped by the throat 16. Then, the damped vibration propagates to theplayer.

Since the styrene-isoprene-styrene block copolymer has excellentvibration damping performance, even though the vibration damper 36 isthin, the vibration damper 36 can contribute to the feel at impact. Thethin vibration damper 36 does not significantly impair the stiffness ofthe frame 4.

The styrene-isoprene-styrene block copolymer is excellent in adhesion toepoxy resins. Therefore, the vibration damper 36 can be firmly joined tothe fiber reinforced layer 34. The firm joining can contribute to thestiffness of the frame 4. The tennis racket 2 having excellent stiffnesshas excellent rebound performance. The player can hit a fast shot byusing the tennis racket 2. The firm joining can also contribute to thedurability of the tennis racket 2.

Another base polymer suitable for use in the vibration damper 36 is anacrylic elastomer. The acrylic elastomer contains an acrylic resin blockas a hard segment and a soft segment. One example of a sheet molded fromthe acrylic elastomer is “PIEZON” (trade name) available from TITECSJAPAN Inc.

The vibration damper 36 whose base material is the acrylic elastomer hasexcellent damping performance. When a player hits a ball with the tennisracket 2, the frame 4 vibrates. The vibration damper 36 graduallydecreases the amplitude of the vibration. In the case of the tennisracket 2, the amplitude of the vibration that propagates to the playeris small. Therefore, the player feels less discomfort when hitting theball with the tennis racket 2. The tennis racket 2 provides an excellentfeel at impact.

Since the acrylic elastomer has excellent vibration damping performance,even though the vibration damper 36 is thin, the vibration damper 36 cancontribute to the feel at impact. The thin vibration damper 36 does notsignificantly impair the stiffness of the frame 4.

The acrylic elastomer is excellent in adhesion to epoxy resins.Therefore, the vibration damper 36 can be firmly joined to the fiberreinforced layer 34. The firm joining can contribute to the stiffness ofthe frame 4. The tennis racket 2 having excellent stiffness hasexcellent rebound performance. The player can hit a fast shot by usingthe tennis racket 2. The firm joining can also contribute to thedurability of the tennis racket 2.

FIG. 6 is a further enlarged sectional view of the tennis racket 2 ofFIG. 5. FIG. 6 shows the throat 16. In FIG. 6, an arrow Ti indicates thethickness of the vibration damper 36. Preferably, the thickness Ti isgreater than or equal to 0.10 mm but less than or equal to 1.00 mm. Anexcellent feel at impact can be achieved by the vibration damper 36having the thickness Ti of greater than or equal to 0.10 mm. In light ofthis, the thickness Ti is more preferably greater than or equal to 0.20mm, and particularly preferably greater than or equal to 0.30 mm. Thevibration damper 36 having the thickness Ti of less than or equal to1.00 mm does not significantly impair the stiffness of the frame 4. Inlight of this, the thickness Ti is more preferably less than or equal to0.80 mm, and particularly preferably less than or equal to 0.60 mm.

In FIG. 3, an arrow Le indicates the length of the vibration damper 36.In light of vibration damping performance, the length Le is preferablygreater than or equal to 30 mm, more preferably greater than or equal to50 mm, and particularly preferably greater than or equal to 60 mm.

The total of the lengths Le of all the vibration dampers 36 in thetennis racket 2 is preferably greater than or equal to 50 mm, morepreferably greater than or equal to 80 mm, and particularly preferablygreater than or equal to 100 mm.

Preferably, the Shore A hardness of the vibration damper 36 is higherthan or equal to 40 but lower than or equal to 95. The vibration damper36 having the Shore A hardness of higher than or equal to 40 does notsignificantly impair the stiffness of the frame 4. In light of this, theShore A hardness of the vibration damper 36 is more preferably higherthan or equal to 45, and particularly preferably higher than or equal to50. An excellent feel at impact can be achieved by the vibration damper36 having the Shore A hardness of lower than or equal to 95. In light ofthis, the Shore A hardness of the vibration damper 36 is more preferablylower than or equal to 90, and particularly preferably lower than orequal to 87. The Shore A hardness of the vibration damper 36 is measuredby using a test piece that contains the same material as that of thevibration damper 36. The measurement is performed in compliance with the“JIS K 6253-3” standards.

Preferably, the elongation rate at break (hereinafter, simply referredto as “elongation rate”) of the vibration damper 36 is higher than orequal to 200%. An excellent feel at impact can be achieved by thevibration damper 36 having the elongation rate of higher than or equalto 200%. In light of this, the elongation rate is more preferably higherthan or equal to 240%, and particularly preferably higher than or equalto 260%. The elongation rate is measured by a tensile test. The tensiletest is performed in compliance with the “JIS K 6251” standards.

Hereinafter, one example of a method of manufacturing the tennis racket2 according to the present invention is described with reference to FIG.7. In this manufacturing method, a mandrel, a tube, a plurality ofprepregs 38, and two films are prepared. Each prepreg 38 is made from aplurality of reinforcement fibers arranged in parallel and a matrixresin. In this manufacturing method, first, the mandrel is inserted intothe tube. The prepregs 38 are sequentially wound around the tube. As aresult of the winding, the prepregs 38 have a tubular shape. FIG. 7shows a tubular prepreg 38 a and a sheet-shaped prepreg 38 b. Two films40 are placed on the sheet-shaped prepreg 38 b. In FIG. 7, theillustration of the mandrel and the tube is omitted.

By rotating the mandrel, the prepreg 38 b is wound around the prepreg 38a. As a result of the winding, the prepreg 38 b has a tubular shape.Each film 40 is sandwiched between the prepreg 38 a and the prepreg 38b. Another prepreg 38 or prepregs 38 is/are wound around the prepreg 38b as necessary.

After the mandrel is removed from the tube, the tube and the prepregs 38are set in a mold. In the mold, gas is injected into the tube, therebyinflating the tube. The prepregs 38 are pressed against the cavitysurface of the mold by the inflation. The prepregs 38 are heated to curethe matrix resin. A molded article is obtained by the curing. The moldedarticle has a reverse shape of that of the cavity surface.

The holes 26 are drilled in the molded article. The molded article isfurther subjected to treatments such as surface polishing and painting,and thereby the frame 4 is obtained. Components such as the grip 6 andthe grommet 10 are attached to the frame 4. Further, the string 12 isstretched on the frame 4, and thus the manufacturing of the tennisracket 2 is completed. The vibration damper 36 of the left-side throat16 is formed by one film 40. The vibration damper 36 of the right-sidethroat 16 is formed by the other film 40.

FIG. 8 is a sectional view of a part of a tennis racket according toanother embodiment of the present invention. FIG. 8 shows a crosssection of a right-side throat 42. The cross-sectional shape of theleft-side throat 42 and the cross-sectional shape of the right-sidethroat 42 are symmetrical with each other. The configuration of eachpart of the tennis racket, except the throats, is the same as that ofthe tennis racket 2 shown in FIG. 1.

The tennis racket includes a fiber reinforced layer 44, a firstvibration damper 46, and a second vibration damper 48. The fiberreinforced layer 44 includes a plurality of reinforcement fibers and amatrix. The reinforcement fibers are typically carbon fibers. Thematerial of the matrix is a resin composition whose base material is anepoxy resin. The first vibration damper 46 is surrounded by the fiberreinforced layer 44. The second vibration damper 48 is surrounded by thefiber reinforced layer 44. The fiber reinforced layer 44 is presentbetween the first vibration damper 46 and the second vibration damper48. The second vibration damper 48 is spaced apart from the firstvibration damper 46.

The material, thickness, and physical properties of the first vibrationdamper 46 are the same as those of the vibration damper 36 shown in FIG.4. The first vibration damper 46 is firmly joined to the fiberreinforced layer 44. The material, thickness, and physical properties ofthe second vibration damper 48 are the same as those of the vibrationdamper 36 shown in FIG. 4. The second vibration damper 48 is firmlyjoined to the fiber reinforced layer 44.

When a player hits a ball with the tennis racket, the frame vibrates.The first vibration damper 46 and the second vibration damper 48gradually decrease the amplitude of the vibration. In the case of thistennis racket, the amplitude of the vibration that propagates to theplayer is small. Therefore, the player feels less discomfort whenhitting the ball with the tennis racket. The tennis racket provides anexcellent feel at impact.

FIG. 9 is a sectional view of a part of a tennis racket according to yetanother embodiment of the present invention. FIG. 9 shows a crosssection of a right-side throat 50. The cross-sectional shape of theleft-side throat 50 and the cross-sectional shape of the right-sidethroat 50 are symmetrical with each other. The configuration of eachpart of the tennis racket, except the throats, is the same as that ofthe tennis racket 2 shown in FIG. 1.

The tennis racket includes a fiber reinforced layer 52, a firstvibration damper 54, and a second vibration damper 56. The fiberreinforced layer 52 includes a plurality of reinforcement fibers and amatrix. The reinforcement fibers are typically carbon fibers. Thematerial of the matrix is a resin composition whose base material is anepoxy resin. The first vibration damper 54 is surrounded by the fiberreinforced layer 52. The position of the first vibration damper 54 isshifted from the center of the throat 50 toward the outer side in thewidth direction (the right side in FIG. 9). The second vibration damper56 is surrounded by the fiber reinforced layer 52. The position of thesecond vibration damper 56 is shifted from the center of the throat 50toward the inner side in the width direction (the left side in FIG. 9).

The material, thickness, and physical properties of the first vibrationdamper 54 are the same as those of the vibration damper 36 shown in FIG.4. The first vibration damper 54 is firmly joined to the fiberreinforced layer 52. The material, thickness, and physical properties ofthe second vibration damper 56 are the same as those of the vibrationdamper 36 shown in FIG. 4. The second vibration damper 56 is firmlyjoined to the fiber reinforced layer 52.

When a player hits a ball with the tennis racket, the frame vibrates.The first vibration damper 54 and the second vibration damper 56gradually decrease the amplitude of the vibration. In the case of thistennis racket, the amplitude of the vibration that propagates to theplayer is small. Therefore, the player feels less discomfort whenhitting the ball with the tennis racket. The tennis racket provides anexcellent feel at impact.

FIG. 10 is a sectional view of a part of a tennis racket according toyet another embodiment of the present invention. FIG. 10 shows a crosssection of a right-side throat 58. The cross-sectional shape of theleft-side throat 58 and the cross-sectional shape of the right-sidethroat 58 are symmetrical with each other. The configuration of eachpart of the tennis racket, except the throats, is the same as that ofthe tennis racket 2 shown in FIG. 1.

The tennis racket includes a fiber reinforced layer 60 and a vibrationdamper 62. The fiber reinforced layer 60 includes a plurality ofreinforcement fibers and a matrix. The reinforcement fibers aretypically carbon fibers. The material of the matrix is a resincomposition whose base material is an epoxy resin. In the cross sectionof FIG. 10, the vibration damper 62 forms a loop. The vibration damper62 is surrounded by the fiber reinforced layer 60. The material,thickness, and physical properties of the vibration damper 62 are thesame as those of the vibration damper 36 shown in FIG. 4. The vibrationdamper 62 is firmly joined to the fiber reinforced layer 60.

When a player hits a ball with the tennis racket, the frame vibrates.The vibration damper 62 gradually decreases the amplitude of thevibration. In the case of this tennis racket, the amplitude of thevibration that propagates to the player is small Therefore, the playerfeels less discomfort when hitting the ball with the tennis racket. Thetennis racket provides an excellent feel at impact.

FIG. 11 is a sectional view of a part of a tennis racket according toyet another embodiment of the present invention. FIG. 11 shows a crosssection of a right-side throat 64. The cross-sectional shape of theleft-side throat 64 and the cross-sectional shape of the right-sidethroat 64 are symmetrical with each other. The configuration of eachpart of the tennis racket, except the throats, is the same as that ofthe tennis racket 2 shown in FIG. 1.

The tennis racket includes a fiber reinforced layer 66 and a vibrationdamper 68. The fiber reinforced layer 66 includes a plurality ofreinforcement fibers and a matrix. The reinforcement fibers aretypically carbon fibers. The material of the matrix is a resincomposition whose base material is an epoxy resin. The vibration damper68 is laminated on the inner surface of the fiber reinforced layer 66.The material, thickness, and physical properties of the vibration damper68 are the same as those of the vibration damper 36 shown in FIG. 4. Thevibration damper 68 is firmly joined to the fiber reinforced layer 66.

When a player hits a ball with the tennis racket, the frame vibrates.The vibration damper 68 gradually decreases the amplitude of thevibration. In the case of this tennis racket, the amplitude of thevibration that propagates to the player is small Therefore, the playerfeels less discomfort when hitting the ball with the tennis racket. Thetennis racket provides an excellent feel at impact.

FIG. 12 is a front view of a tennis racket 70 according to yet anotherembodiment of the present invention. A head 72 of the tennis racket 70includes a vibration damper 74. The vibration damper 74 is arranged oversubstantially the entire head 72, except a yoke 76. Throats 78 of thetennis racket 70 include no vibration damper. Alternatively, in thetennis racket 70, not only does the head 72 include the vibration damper74, but the throats 78 may each include a vibration damper.

FIG. 13 is an enlarged sectional view taken along line XIII-XIII in FIG.12. The head 72 includes a fiber reinforced layer 80 and the vibrationdamper 74. The fiber reinforced layer 80 includes a plurality ofreinforcement fibers and a matrix. The reinforcement fibers aretypically carbon fibers. The material of the matrix is a resincomposition whose base material is an epoxy resin. The vibration damper74 is surrounded by the fiber reinforced layer 80. The material,thickness, and physical properties of the vibration damper 74 are thesame as those of the vibration damper 36 shown in FIG. 4. The vibrationdamper 74 is firmly joined to the fiber reinforced layer 80.

When a player hits a ball with the tennis racket 70, the frame vibrates.The vibration damper 74 gradually decreases the amplitude of thevibration. In the case of the tennis racket 70, the amplitude of thevibration that propagates to the player is small. Therefore, the playerfeels less discomfort when hitting the ball with the tennis racket 70.The tennis racket 70 provides an excellent feel at impact.

FIG. 14 is a front view of a tennis racket 82 according to yet anotherembodiment of the present invention. A head 84 of the tennis racket 82includes a first vibration damper 86 and a second vibration damper 88.The position of the first vibration damper 86 is shifted to the rightfrom the center of the head 84. The position of the second vibrationdamper 88 is shifted to the left from the center of the head 84. Thefirst vibration damper 86 and the second vibration damper 88 aresymmetrical with each other.

The material, thickness, and physical properties of the first vibrationdamper 86 are the same as those of the vibration damper 36 shown in FIG.4. The first vibration damper 86 is firmly joined to the fiberreinforced layer. The material, thickness, and physical properties ofthe second vibration damper 88 are the same as those of the vibrationdamper 36 shown in FIG. 4. The second vibration damper 88 is firmlyjoined to the fiber reinforced layer.

When a player hits a ball with the tennis racket 82, the frame vibrates.The first vibration damper 86 and the second vibration damper 88gradually decrease the amplitude of the vibration. In the case of thetennis racket 82, the amplitude of the vibration that propagates to theplayer is small. Therefore, the player feels less discomfort whenhitting the ball with the tennis racket 82. The tennis racket 82provides an excellent feel at impact.

EXAMPLES Example 1

The tennis racket shown in FIGS. 1 to 6 was obtained. The racketincludes a fiber reinforced layer and a vibration damper. The fiberreinforced layer includes reinforcement fibers and a matrix whose basematerial is an epoxy resin. As the vibration damper, a commerciallyavailable sheet (the aforementioned “KRAIBON” (trade name)) was used.The material of the vibration damper is a polymer composition whose basematerial is a styrene-isoprene-styrene block copolymer. The thickness ofthe vibration damper is 0.5 mm.

Example 2

A tennis racket of Example 2 was obtained in the same manner as inExample 1, except that a different commercially available sheet (tradename “PIEZON”) was used as the vibration damper. The material of thevibration damper is a polymer composition whose base material is anacrylic elastomer.

Comparative Example 1

A tennis racket of Comparative Example 1 was obtained in the same manneras in Example 1, except that a different commercially available sheetwas used as the vibration damper. The material of the vibration damperis a polymer composition whose base material is chlorinatedpolyethylene.

Comparative Example 2

A tennis racket of Comparative Example 2 was obtained in the same manneras in Example 1, except that the tennis racket of Comparative Example 2includes no vibration damper.

Examples 3 to 8

Tennis rackets of Examples 3 to 8 were obtained in the same manner as inExample 1, except that the position of the vibration damper was variedas shown in Table 2 below.

Evaluation

Players did a rally by using each tennis racket. The players evaluatedthe rebound performance (flight), vibration absorption performance, feelat impact, and control performance of each racket. The evaluationresults are shown in Tables 1 and 2 below.

In Tables 1 and 2, the greater the numerical value, the higher theevaluation.

TABLE 1 Evaluation results. Comparative Comparative Example 1 Example 2Example 1 Example 2 Material SIS AC PE — Position FIG. 3 FIG. 3 FIG. 3 —FIG. 4 FIG. 4 FIG. 4 — Rebound 8 6 4 8 performance Vibration 8 8 8 3absorption performance Feel at impact 9 8 6 4 Control 8 8 7 5performance Overall 9 7 6 5 evaluation SIS: Styrene-isoprene-styreneblock copolymer AC: Acrylic elastomer PE: Chlorinated polyethylene

TABLE 2 Evaluation Results. Ex- Ex- Ex- Ex- Ex- Ex- ample ample ampleample ample ample 3 4 5 6 7 8 Material SIS SIS SIS SIS SIS SIS PositionFIG. 8 FIG. 9 FIG. 10 FIG. 11 FIG. 12 FIG. 14 FIG. 13 Rebound 7 7 7 8 67 performance Vibration 9 9 9 7 9 8 absorption performance Feel atimpact 9 9 9 8 9 9 Control 8 8 8 8 8 8 performance Overall 8 8 8 7 7 8evaluation SIS: Styrene-isoprene-styrene block copolymer AC: Acrylicelastomer PE: Chlorinated polyethylene

It is clear from Tables 1 and 2 that the tennis racket in each Exampleis well-balanced in various performances. These evaluation resultsclearly indicate the superiority of the present invention.

The racket according to the present invention can be used in varioussports, such as soft tennis, squash, and badminton. The foregoingdescription is in all aspects illustrative, and various modificationscan be made without departing from the essential features of theinvention.

What is claimed is:
 1. A racket comprising a frame, wherein the frameincludes a fiber reinforced layer and a vibration damper joined to thefiber reinforced layer, the fiber reinforced layer includes areinforcement fiber and a matrix whose base material is an epoxy resin,and a material of the vibration damper is a polymer composition whosebase material is a styrene-isoprene-styrene block copolymer or anacrylic elastomer.
 2. The racket according to claim 1, wherein the frameincludes a head, two throats, and a shaft, and each throat includes thevibration damper.
 3. The racket according to claim 1, wherein athickness of the vibration damper is greater than or equal to 0.10 mmbut less than or equal to 1.00 mm.